Continuity mistake: In the scene towards the end of the film where we see Slade's body fall, it falls onto a submerged rock just below the surface of the water and there is a splash of water. In the next shot Tarzan looks down from the cliff above and Slade's body is on a large dry rock, a little distant from where the body originally fell.
Continuity mistake: In the scene towards the end of the film where Tarzan is having a fight to the death with Slade, Tarzan manages to put the wire noose around Slade's neck. Next shot you see is Slade losing his balance at the edge of the cliff and about to fall. The noose somehow comes off Slade's neck and is discarded by Tarzan (to the right side): it falls on the cliff and appears to stay there. The next shot, Slade falls to his death and his body is on a rock below. Mysteriously the pole with the noose falls out of Slade's hand into the water.